One of the more famous areas of Tokyo is the Tsukiji market, often considered to be the largest wholesale fish market in the world. In addition to this market, there is also a wholesale fruit and veg market, restaurants, and retail shops in the market area. The streets around the market are full of yet more shops and restaurants.
Here is a kitchen knife store where the knife maker is polishing each blade by hand on a whetstone, there a retailer selling shop-made bonito. A street over a delivery cart has just stopped off at a sushi restaurant with a supply of tuna straight from the wholesale market, and next door are vats of pickles and a butcher shop. On the corner a small stand has tempura and soba on offer, and a bit further along are vats of seaweed.
All of this combines to make for a sensual feast as you merge with the flow of traders, shoppers, and tourists. If you were not hungry to start with you are now, and the question becomes one of time and cost. The best places have high prices and long lines for a seat, and at the other end of the spectrum there are street stands offering quick bites on a budget to eat as you keep going. It is impossible to go wrong, and with all the choices it is impossible to go right, because selecting one means missing another.